JP2008055905A - Method of forming phase change ink image on self-laminating recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of obtaining images containing hot melt ink which overcome or at least ease the disadvantageous points of the well-known method. <P>SOLUTION: The method creates an image on a recording medium (2) comprising a support (15, 16) having thereon a porous fusible layer (17), using an ink composition that is solid at room temperature and liquid at elevated temperature comprising the steps of generating droplets of the ink composition with an ink jet print head (4), and includes the steps of transferring the droplets of the ink composition to the surface of the fusible layer (17), thermally treating the recording medium such that the ink transferred to fusible layer passes into the medium away from the surface of the fusible layer whilst the fusible layer remains substantially unfused, and when the ink has passed into the medium, and treating the recording medium to fuse the fusible layer to become a protective overcoat (17'). The invention also relates to a system for creating an image on a recording medium. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method of creating an image on a recording medium having an ink composition that is solid at room temperature and liquid at high temperature. The present invention also relates to a system for producing an image on a recording medium having the ink composition.

  A method for creating an image on a recording medium with an ink composition (also called “hot melt” or “phase change ink”) that is solid at room temperature and liquid at high temperature is described in US Pat. No. 6,497,940. (Patent Document 1). The patent document 1 describes a recording medium for an ink composition having improved transparency, improved resistance to surface scratches, and improved ink adhesion. The recording medium is polyethylene coated with a lower receptor layer comprising 82-97 wt% silica and 3-18 wt% PVA, polyvinylpyrrolidone, polyacrylamide, methylcellulose, or gelatin. It has a terephthalate support. The optional upper layer has 32-70 wt% matrix polymer, 15-52 wt% inorganic particulate material, 5-53 wt% soft polymer blend. The term “soft polymer blend” describes a polymer or mixture of polymers that softens during the image transfer stage of printing. Softening allows the ink composition and upper layer to conform chemically and physically for mechanical durability reasons. The soft polymer matrix should be soft enough so that the ink composition and coating are closely correlated, and sufficiently rigid to prevent scratching and sticking to adjacent films.

While this known method is suitable for obtaining adequate mechanical durability, the disadvantage of the method is that it was printed by storing the printed media at 35 ° C. for weeks or months, for example. The print quality is degraded when the medium is subjected to a thermal load. For example, it can be seen that the gloss level is significantly reduced and that local artifacts occur in the printed image.
US 6,497,940

  The present invention aims to provide an improved method of obtaining images with hot melt inks that overcomes or at least mitigates the disadvantages of known methods. For this reason, an ink-jet printing method has been invented that uses a storage medium having a support having a porous soluble layer above it. The method includes the steps of: generating an ink composition droplet with an inkjet printhead; transferring the ink composition droplet to the surface of the soluble layer; Heat-treating the recording medium such that the transferred ink passes into the medium away from the surface of the soluble layer, while the soluble layer remains substantially undissolved, and the ink enters the medium Treating the recording medium to dissolve the soluble layer so as to provide a protective overcoat upon entry.

  With such a method, compared to prior art methods, the heat treatment causes the ink to enter the media and be substantially free of ink, ie at least (typically 90-99% of the hot melt ink. Consists of an upper layer that does not have an ink meltable solvent composition. This upper layer is then dissolved (optionally together with other parts of the medium) to become a protective overcoat, the dissolution being a known physical or chemical that allows the porous layer to become a dissolved layer. It can be done by chemical methods. In this way, a continuous film (i.e., a film where the pores or gaps mostly disappear) is made to substantially block the interaction between the environment and the ink trapped in the media. Next to very good mechanical durability, it is believed that very durable high gloss can be achieved with the method according to the present invention even in relatively high thermal environments. .

  The inventor understands that a porous soluble layer, i.e., a layer having pores or gaps that allow the passage of fluid ink itself, is not sufficient to reach the results that can be obtained with the present invention. ing. It is essential that the recording medium is heat treated so that the ink enters the medium away from the surface of the soluble layer. Otherwise, the ink can remain on the surface and therefore cannot easily be provided with an upper layer without ink. However, the heat treatment should be such that the ink enters the medium while the soluble layer remains substantially undissolved. This prevents premature coalescence of the ink and soluble layer known from the prior art. The heat treatment itself is not limited to any kind of treatment, and may be, for example, radiation treatment, contact treatment, conductive treatment, or the like. This treatment can be performed before, simultaneously with, or after the ink is transferred to the surface of the recording medium (medium preheating), or a combination of such methods can be used to transfer the hot melt ink to the medium. It can be used as long as it leads to an increase in the temperature of (part of) the medium that allows it to enter and prevent substantial dissolution of the soluble layer.

  In the method according to the invention, the treatment of dissolving the porous layer should not be performed until the ink has entered the medium so as to create an upper layer without ink. However, the process of dissolving the porous layer and the heat treatment that allows the ink to enter the medium are achieved, for example, by a one-step heat treatment by passing the printed recording medium through a heated set of rollers, etc. It is noted that it can be done. That is, by applying such a heated roller, the viscosity of the ink droplets present on the surface of the porous layer exceeds the melting point of the ink (for example, an ink having a melting point of 90 ° C. is heated to 120 ° C.). Typically about 10 mPa.s. It can be forced down to a value that is s. Such a high temperature may also be sufficient to dissolve a soluble layer composed of a polyester polymer having a glass transition temperature of, for example, 65 ° C., but the time scale for the transfer of fluid ink to the medium is soluble ( It is typically significantly (10 to 1000 times) shorter than the time scale for dissolution of the (polymer) layer. Thus, what appears to be a single heat treatment at first glance, has the choice of the correct material to be used in a particular environment and the ink to the media to give an ink-free upper layer Can then be considered as a first treatment to allow entry, and then dissolve at least the upper part of the fusible layer, i.e. the non-ink layer, of the layer so as to form a closed protective overcoat Processing continues.

  Ink compositions that are solid at room temperature and liquid at high temperatures are generally known. Examples of such ink compositions are given in EP 1 067 157 and publication number 497067 in the September 2005 volume of Research Disclosure (published by Park Avenue South, New York, USA, published by Emsworth Design Inc.). The illustrated ink has a mixture of a crystalline matrix material, an amorphous binder, and a gelling agent.

  In order to print the ink composition using an inkjet head, the ink composition needs to be in a fluid state. This would require an inkjet head specification that can operate at temperatures above the ink melting point, typically 90-140 ° C. For this reason, a printhead having a heated pressure chamber filled with fluid ink and connected to the nozzles can be used. The pressure required to fire a droplet is generated by firing a transducer, such as a piezoelectric transducer.

  The recording medium used in the method according to the invention has a support for the porous soluble layer. Such a support can be opaque, translucent, or transparent. For example, plain paper, resin-coated paper, and various plastics can be used. The plastic comprises a polyester resin such as poly (ethylene terephthalate), a fluoro resin such as poly (ethylene naphthalate), polycarbonate resin, poly (tetrafluoroethylene), metal foil, vinyl, fiber, layered or coextruded support. Have. Inkjet paper that can be used as a support for the purposes of the present invention is also described in the TAPPI Coating Conference proceedings in 2002, ie, articles by Western Michigan University Hyun-Kook Lee, Margaret Joyce, Paul Fleming, and John Cameron. The

  The soluble layer can have soluble polymer particles and the like. The particles can have any size, and when configured as a layer, the particles are applied to the pores or gaps, allowing fluid ink to enter the media, creating an ink free upper layer, Moreover, it fuse | melts so that a continuous protective film may be formed at the time of a dissolution process. Typical particle sizes are in the range of 1 to 10 micrometers.

  It is noted that US 6,497,480 describes an ink jet recording element having a support. The support has a porous ink retaining layer and a soluble porous ink transport layer in succession, the ink transport layer comprising soluble polymer particles and a film-forming hydrophobic binder. Have. US 6,811,253 describes an ink jet printing method. The method includes printing onto a recording medium having an ink receptive layer and an upper protective layer and heating the printed image to form a stable image protective coating. The upper protective layer has a particulate polymer bead having a film forming temperature of 100-120 ° C. with a hydrophilic binder. The present invention conveniently protects inkjet images.

  However, the technical disclosure of these patents is limited to specifications for water or solvent based inks. Such inks are completely different from hot melt inks not only in their intrinsic properties, but also in their reaction when printed on media. In particular, such inks do not have the problem of gloss degradation when printed on dedicated inkjet glossy media. Further, since such ink is a fluid at room temperature, it easily moves to the ink receiving layer via the soluble ink transport layer. Of course, neither reference mentions a heat treatment that allows ink to enter the recording medium. Hence, the method according to the invention is not known from the disclosure of such referenced documents and is not prevented in advance.

  In one embodiment of the present invention, the recording medium used has a support having a base layer and an ink receiving layer thereon. The base layer may be a layer suitable to provide appropriate mechanical strength or other properties as required (depending on the application). The ink receiving layer is designed to absorb ink that enters the media. Such an absorbing layer can be configured in many shapes as long as the ink interacts with the ink so that it can be partially or completely absorbed in the layer. In a further embodiment, the ink receiving layer is a microporous layer. Such layers have pores or gaps having a cross section around the (sub) micrometer range. Such layers can have organic or inorganic particles and typically have a thickness that is from about 1 μm to about 5 μm. Organic particles that can be used include acrylic resins, styrene resins, cellulose derivatives, polyvinyl resins, ethylene allyl copolymers, and polycondensation polymers. Examples of inorganic particles that can be used in the ink receiving layer include silica, alumina, titanium dioxide, clay, calcium carbonate, barium sulfate, or zinc oxide. The microporous ink receptive layer comprises about 20% to about 100% particles and about 0% to about 80% polymeric binder, desirably about 80% to about 95% polymeric particles and about 20% to 5%. % Polymer binder. The polymeric binder can be a hydrophilic or hydrophobic polymer (depending on the type of ink for the designed receiving medium), for example, poly (vinyl alcohol), poly (vinyl pyrrolidone), gelatin, cellulose ether , Poly (oxazoline), poly (vinylacetamide), partially hydrolyzed poly (vinyl acetate / vinyl alcohol), poly (acrylic acid), poly (acrylamide), poly (alkylene oxide), sulfonated or Phosphorated polyester and polyethylene, casein, zein, albumin, chitin, chitosan, dextran, pectin, collagen derivatives, colloidian, agar, kuzukon, guar, carrageenan, tragacanth, xanthan, la Than, and is equivalent.

  In one example, the porous soluble layer comprises a thermoplastic material. This has the advantage that heat treatment can be used to dissolve the layer to form a continuous protective overcoat. Depending on the specific application of the recording medium, the material constituting the fusible layer can in principle be a thermoplastic material composed solely of a thermoplastic compound, or a polymer or other additive. (In any proportion) may be a thermoplastic material composed of a combination of a film or the like and a thermoplastic composite. For example, if the recording medium is subjected to a temperature above 80 ° C., it is recommended that the thermoplastic material be used with a glass transition temperature above 80 ° C., in particular above 90 ° C. Examples of suitable thermoplastic composites include polyester, polyester amide, polyethylene, and polyurethane.

  In other embodiments, the fusible layer is provided on the support via screen printing techniques. Surprisingly, the porosity is provided by using a screen printing technique known per se in a very simple and convenient way, so that the fluid hot melt ink can enter the recording medium. While being sufficiently “dense” to allow proper dissolution under moderate loads, such as moderate temperature and / or increased pressure. Other techniques, such as resin rod coating, or resin dispersions in aqueous or non-aqueous solvents, are optional in addition to mechanical methods that force pores or gaps in the soluble layer. Although it can be given for the result, it is less practical in use.

  In another embodiment, the ink composition has a meltable ink solvent having at least a material that can be obtained in the crystal phase at 25 ° C. Desirably, the ink solvent crystalline material and the material comprising the soluble layer are substantially not mixed at 25 ° C. That is, both materials do not spontaneously mix at the molecular level at that temperature. In this way, the durability is further improved.

  In other embodiments, the fusible layer comprises a material having a glass transition temperature greater than 50 ° C. With this glass transition temperature, the recording media can be prevented from sticking when the stack of media is exposed to temperatures up to about 50 ° C. On the other hand, it is desirable that the glass transition temperature be lower than 70 ° C. to allow the layer to melt by applying a moderate temperature increase.

  The invention also relates to a system for producing an image on a recording medium having a support having a porous soluble layer above it. The system has an inkjet printhead that is tuned to eject droplets of an ink composition that is solid at room temperature and liquid at high temperatures, and to transfer the droplets to the surface of the soluble layer. . The system optionally includes an intermediate member that temporarily receives droplets of the ink composition prior to the preceding transfer to the fusible layer, and further includes a heat treatment element for thermally treating the recording medium. A control arrangement and a means of transport. The control arrangement controls the heat treatment element so that the ink transferred to the soluble layer leaves the surface of the soluble layer and enters the medium while the soluble layer remains substantially undissolved. To. The transporting means transports the recording medium from the ink transfer position to the dissolving position close to the dissolving means. The dissolving means can treat the recording medium to dissolve the soluble layer so as to be a protective overcoat. The control arrangement may be part of the hardware designed to control the heat treatment of the recording medium (such as the shape of an ASIC). However, the control arrangement need not be a single piece of hardware and can be distributed across the system. Furthermore, such an arrangement may be provided in the form of software running on one or more processors (general and / or programmable) in smaller or larger portions. The software is used to control the corresponding hardware. All types of control arrangements can be properly designed to properly control the heat treatment of the recording medium consistent with the present invention.

  The optional intermediate member may be a belt or a drum, optionally an intermediate medium known from US 2003/0234841 A1 (see FIG. 1, element 14) or US 6,905,203 (see FIG. 1, element 1), etc. Having an elastomer upper layer. When using such an intermediate medium, the entire image can be printed on the intermediate member before being transferred to the recording medium. Using an intermediate member has the advantage that the process is more reliable and not dependent on changes in the type of recording medium, in particular for clogging of the nozzles due to dust from the paper.

  The invention is further illustrated with the following non-limiting figures and examples.

  Example 1 illustrates the process of making a recording medium for use in the method according to the invention.

  Example 2 illustrates the results that can be achieved with the method according to the invention.

  FIG. 1 is a diagram illustrating an ink jet printer. According to this embodiment, the printer has a roller 1 that is used to support a recording medium 2 and transport it along a carriage 3. The carriage 3 has a carrier 5 on which four print heads 4a, 4b, 4c and 4d are fitted. Each print head 4a, 4b, 4c, 4d has a respective color, in this case cyan (C), magenta (M), yellow (Y), and black (K). The print heads 4a, 4b, 4c, 4d are heated using a heating element 9 fitted against the back of each print head 4a, 4b, 4c, 4d. The temperature of the print heads 4a, 4b, 4c, 4d is maintained at an appropriate level by applying the central control unit 10 (controller). The roller 1 can rotate around its axis as indicated by arrow A. In this way, the receiving medium can be moved in the sub-scan direction (often referred to as the X direction) relative to the carrier 5 and to the print heads 4a, 4b, 4c, 4d. The carriage 3 can be moved in reciprocation using a suitable drive mechanism (not shown) in the direction indicated by the double arrow B which is parallel to the roller 1. In this way, the carrier 5 is moved over the guide rods 6 and 7. This direction is generally referred to as the main scan direction or the Y direction. In this way, the receiving medium 2 can be completely scanned by the print heads 4a, 4b, 4c, 4d. According to this embodiment shown in FIG. 1, each print head 4a, 4b, 4c, 4d has a plurality of internal ink chambers (not shown), each having its own outlet opening (nozzle) 8. . The nozzles 8 in this embodiment form a row for each printhead that is perpendicular to the axis of the roller 1 (ie, the row extends in the sub-scan direction). In one practical embodiment of inkjet, the number of ink chambers per printhead is many times greater, and the nozzles 8 are arranged in two or more rows. Each ink chamber has a piezoelectric transducer (not shown). The piezoelectric transducer can generate a pressure wave in the ink chamber so that ink droplets are ejected from the nozzles of the associated chamber in the direction of the receiving medium 2. The converter can be image-wise actuated via an associated electric drive circuit (not shown) by application of the central control unit 10. In this way, an image made with ink droplets can be formed on the receiving medium 2. When the receiving medium 2 is printed using such a printer where ink droplets are ejected from the ink chamber, this receiving medium 2 or some portion thereof is (virtually) pixel rows and It is divided into fixed positions that form a fixed field of pixel columns. According to one embodiment, the pixel row is perpendicular to the pixel column. Thus, each individual location created can be provided with one or more ink droplets. The number of positions per unit of length in a direction parallel to the pixel rows and pixel columns is, for example, 400 × 600 d. p. i. Referred to as the resolution of the printed image denoted as ("dots per inch"). When the carrier 5 is moved and moved relative to the receiving medium 2 by actuating a row of printhead nozzles 8 in an inkjet printer in the image direction, the image produced with the ink droplets or some portion thereof is Formed on the recording medium 2 or on a strip having a width at least equal to the length of the row of nozzles.

  The roller 1 is provided with a radiation heater 12 therein, which is configured to heat the receiving medium 2 by heating around the roller that radiates heat to the medium in contact with the roller. In this way, the recording medium can be treated to allow hot melt ink to enter the medium immediately after the corresponding ink droplet impacts the surface of the recording medium. The heater 12 is controlled by one control software incorporated in the controller 10. In this embodiment, the software takes advantage of a memory having various combinations of inks that can be used in printers and recording media that can be used in accordance with the present invention. Each combination is associated with a dedicated setting of roller temperature, which is a parameter to be controlled directly in the implemented system. That is, the temperature of the roller surface is measured using a contact sensor (not shown) and compared to a preprogrammed temperature setting. Depending on the difference between the pre-programmed temperature setting and the measured temperature, the heater is controlled to reduce this difference as much as necessary.

  FIG. 2 is a schematic diagram of the interaction of a recording medium and phase change ink according to one embodiment of the present invention. FIG. 2A shows a recording medium having a base layer 15 and an ink receiving layer 16 (which together forms a support in the present invention) and a soluble layer 17. The base layer in this case is a simple paper substrate. The ink receiving layer is generally a commonly used construction with 90 wt% silica nanoparticles in the range of 300 to 30 nanometers at 10 wt% polyvinyl alcohol. High weight fraction particulate material with respect to binder fraction results in a high porosity layer with excellent ink retention properties.

  The soluble layer is a film having thermoplastic polymer particles (polyester resin; Mn = 90, Tg = 55 ° C.). Such particles have an average dimension of 2-5 μm and start with an aqueous dispersion of the particles (10% by weight resin in water) to give a film having a thickness of about 20 μm, on the support Rod coated. Above the fusible layer 17 is a layer (20) of solid phase change ink droplets jetted onto the surface of the recording medium.

  FIG. 2B shows the situation after the heat treatment of the recording medium. The ink droplets above the soluble layer leave the surface of the soluble layer that remains substantially undissolved and enter the recording medium, in this case the ink receiving layer 16. In this particular case, after the ink has entered the medium, the fully soluble layer is substantially free of ink. However, it is noted that the invention described in the appended claims also covers the extent that only the upper layer of the soluble layer is substantially free of ink.

  FIG. 2C shows the situation after the dissolution treatment of the recording medium. The fusible layer is dissolved to form a closed protective overcoat 17 '. In this case, the complete layer 17 is dissolved to become the layer 17 '. However, it is understood that the present invention as set forth in the appended claims also covers the extent that only the layer without ink above the soluble layer is dissolved to be a protective overcoat. Should be.

  FIG. 3 is a schematic diagram of a system for creating an image in accordance with the present invention. On the left hand side, the ink jet printer detailed with reference to FIG. 1 has a roller 1 initially heated to move one of its most important components: the recording medium 2 and the print head 4. It is represented by showing. The system further includes a melt roller arrangement having a head roller 36 and a back roller 35. Both rollers are slightly pressed together (typically a line pressure of 250 Newtons per meter) by suitable pressure supply means (not shown). Both rollers are provided with an elastic surface layer, in this example a soft silicon elastomer layer (20 ShA hardness). The transport roller 1 can transport the printed recording medium 2 from the ink transfer position 30 to the dissolution position 40. The roller is heated to a temperature of about 140 ° C. The temperature is in this case (the resin selected for the soluble layer is a polyester resin having a Tg of 55 ° C.) at least the upper layer of the soluble layer so as to dissolve into a continuous protective overcoat. Appropriate to heat.

  Example 1 illustrates the process of making a recording medium for use in the method according to the invention. The resin is typically selected with a Tg (glass transition temperature) that is 50-70 ° C. As an example, a polyester resin exemplified as resin number 3 in Table 2 in International Patent Application PCT / EP2006 / 062614 is selected. A 10% resin dispersion in water (10% resin by weight) is made so that the resin particles have an average size below 1 micron (which can be easily identified with a light scattering particle sizer). It is done. The viscosity of this dispersion is approximately the same as that of water itself, and the appearance of the dispersion is milky.

  A clean screen commonly used in screen printers is placed on top of a suitable substrate, in this case Kodak Instant Dry Glossy photo paper 190g. By supporting the substrate and applying moderate pressure on the screen framework, it is ensured that there is good contact between the screen and the substrate. The screen in this case is made with monofilaments having inert fibers. The filament is 40 microns wide leaving an opening of 20 x 20 micrometers.

  The resin dispersion is applied on the side of the screen facing away from the substrate so that it cannot yet wet the substrate. With a rubber squeegee, the dispersion is applied across the screen in one action. It is important that the squeegee does not dry, as drying the squeegee will cause defects in the layer being coated. Excess dispersion is removed from the screen because it can come into contact with the substrate and result in a layer of coating that is wrinkled or too thick. After the coating stage, the screen and substrate are left in place to allow drying. This can be done under ambient conditions. After drying, the screen is removed. This method results in a recording medium having a soluble layer on a substrate as a support, the soluble layer having a width of about 40 × 40 micrometers and a height of about 15-20 micrometers in a fixed pattern. Polyester resin dots and a space of several microns between the dots. The thickness of the dots can be variable, for example, by changing the amount of resin in the dispersion.

  Other coating techniques to obtain a soluble layer can also be successfully applied. For example, it is recognized that rod coating techniques or cast coating techniques can be applied to obtain a recording medium for use in the present invention when both techniques start with an aqueous or non-aqueous medium as a carrier for the soluble material. The present invention can also be applied to a part of a recording medium. For example, if the overcoat is desired only for certain smaller images of the complete image (eg, the company name above the letter that should appear high glossy), the media is only in the position corresponding to the company name Can be made with a soluble layer.

  Example 2 illustrates the results that can be achieved with the method according to the invention. With the screen printing method described above (Example 1), four recording media are made. Four different types of resins are selected for the soluble layer. That is, polyesteramide resin having resin number 3 in Table 2 in international patent application PCT / EP2006 / 062614, Mn (number average molecular weight) of resin number 1, 900 in the same table in the patent document, and Tg of 65 ° C. As well as partially crystalline polyolefin resins (commercially available from Dow Chemical Corporation under the trade name “Engege”).

  Each of the four such materials is printed with three different hot melt inks having the configuration as given in Table 1. Each of such ink compositions has a crystalline material (K), an amorphous material (A), and a gelling agent (G). The ink composition is provided with a dye (Kl) that is Macrolex Rot (Bayer) in the case of Ink Compositions I and III, and Orasol Blau (Ciba-Geigy) in the case of Composition II. In addition, the three ink compositions are provided with a wetting agent (V) BYK307 (Byk Chemie). The chemical formulas for the crystalline matrix material (K), the amorphous binder (A), and the gelling agent (G) are given in Tables 2, 3a and 1 of EP 1 067 157, respectively.

インクは、温度３５℃において維持される記録媒体に対して温度１３０℃において放出される。以降、記録媒体は、９０℃において維持されるオーブンまで動かされる。３０秒後、インクは、媒体へと入れられ、１１０℃において維持されるオーブンまで動かされる。そこでインクは、記録媒体のインクを有さない層を溶解するよう十分であるよう９０秒間とどまる。続いて、インクは、周囲条件にもたらされる。

The ink is discharged at a temperature of 130 ° C. against a recording medium maintained at a temperature of 35 ° C. Thereafter, the recording medium is moved to an oven maintained at 90 ° C. After 30 seconds, the ink is placed into the media and moved to an oven maintained at 110 ° C. The ink then stays for 90 seconds to be sufficient to dissolve the ink free layer of the recording medium. Subsequently, the ink is brought to ambient conditions.

  Printed and currently “sealed” recording media is brought into an oven at a temperature of 45 degrees to test durability under thermal load. Image quality is checked every 24 hours. The first relevant characteristic of image quality is the gloss level (eg, can be measured using a Hunter 75 ° gloss meter according to TAPPI procedure T 480 OM-92). Another characteristic is that, in some cases, white spots, which are the crystalline effect of the crystalline material in the ink solvent, are seen. During the first few days, a slight degradation of gloss level (typically 70-60%) will occur. However, this reduction in gloss is hardly noticeable by the naked human eye. The gloss level is then kept substantially constant up to a heat load of 800 hours. There is no white spot that can be noticed with the naked human eye.

1 is a schematic view of an inkjet printer having a plurality of print heads. FIG. 2 is a schematic diagram of an embodiment of a method according to the present invention. FIG. 2 is a schematic diagram of an embodiment of a method according to the present invention. FIG. 2 is a schematic diagram of an embodiment of a method according to the present invention. 1 is a schematic view of an inkjet printer and a melting station. FIG.

Explanation of symbols

2 Receiving medium 15 Base layer 16 Ink receiving layer 17 ′ Protective overcoat layer 20 Ink droplet layer

Claims (9)

A method of creating an image on a recording medium having a support having a porous soluble layer thereon using an ink composition that is solid at room temperature and liquid at high temperature,
Generating droplets of the ink composition with an inkjet printhead;
Transferring the droplets of the ink composition to the surface of the soluble layer;
The recording so that the ink transferred to the soluble layer passes away from the surface of the soluble layer to the medium while the soluble layer remains substantially undissolved. Heat treating the medium;
Treating the recording medium to dissolve the soluble layer into a protective overcoat when the ink passes through the medium;
Having
Method. The recording medium used has a base layer and a support having an ink receiving layer above the base layer,
The method of claim 1. The ink receiving layer is a microporous layer;
The method of claim 2. The fusible layer has a thermoplastic material,
4. A method according to any one of claims 1 to 3. The fusible layer is provided on the support via a screen printing technique,
5. A method according to any one of claims 1 to 4. The ink composition used has a meltable ink solvent having at least a material that can be obtained in the crystal phase at 25 ° C.
6. A method according to any one of claims 1-5. The crystalline material of the ink solvent and the material of the soluble layer are substantially immiscible at 25 ° C.
The method of claim 6. The fusible layer comprises a material having a glass transition temperature higher than 50 ° C.,
8. A method according to any one of claims 1 to 7. A system for creating an image on a recording medium having a support having a porous soluble layer thereon,
An inkjet printhead that is tuned to eject droplets of an ink composition that is solid at room temperature and liquid at high temperatures, and to transfer the droplets to the surface of the soluble layer;
Optionally, an intermediate member that temporarily receives the droplets of the ink composition prior to the transfer to the soluble layer,
Furthermore, it has a heat treatment element for thermally treating the recording medium, a control arrangement, and a transportation means,
The control arrangement controls the heat treatment element such that the ink transferred to the soluble layer enters the medium away from the surface of the soluble layer, while the soluble layer is substantially To remain undissolved in the
The transport means transports the recording medium from an ink transfer position to a dissolution position proximate to a dissolution means capable of treating the recording medium to dissolve the soluble layer as a protective overcoat;
system.

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